Development
In April 1942, the Yakovlev design bureau was instructed to design a twin-engined utility transport aircraft to supplement smaller single-engined aircraft such as the Polikarpov U-2. The design was required to be simple to build and operate. Design and construction work proceeded extremely quickly, with the first protoype Yak-6 flying in June 1942. It passed its State Acceptance Tests in September that year and was quickly cleared for production.
The Yak-6 was a cantilever low-wing monoplane of all-wood construction with fabric covering. It had a retractable tailwheel undercarriage, with the main wheels retracting rearwards into the engine nacelles. The horizontal tail was braced. It was powered by two 140 hp Shvetsov M-11F radial engines driving two bladed wooden propellers, with the engine installation based on Yakovlev's UT-2 primary training aircraft. In order to minimise the use of scarce resources, the aircraft's fuel tanks were made of chemical-impregnated plywood rather than metal or rubber. Many Yak-6s were fitted with fixed landing gear.
The aircraft appeared in two versions, one as a transport and utility aircraft for the supply of partisans, transport of the wounded, and for liaison and courier services. It could accommodate two crew side-by-side in an enclosed cockpit with capacity to carry four passengers or 500 kg (1,100 lb) or cargo. The second version was a light night bomber (designated NBB - nochnoy blizhniy bombardirovshchik - Short Range Night Bomber), capable of carrying up to 500 kg of bombs on racks under the wing centre sections and with a defensive armament of a single ShKAS machine gun in a dorsal mounting. A total of 381 examples were built with production ending in 1943.
A few examples of an improved version of the Yak-6 with swept outer wings were flown, with the modified version sometimes known as the Yak-6M. The Yak-6M led to the larger Yak-8 which flew in early 1944.
Read more about this topic: Yakovlev Yak-6
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